JPS5936656B2 - Polypropylene Distillate Seibutsu - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene resin composition having excellent rigidity, heat resistance, and impact resistance.

More specifically, when compounding barium sulfate and talc-based inorganic fillers with crystalline polypropylene resin, adding glycerin fatty acid ester as a second component improves the physical properties of the molded product, especially its rigidity, impact resistance, and surface gloss. This is a polypropylene resin composition blended with an inorganic filler that has improved heat aging resistance and excellent heat resistance properties. Various methods have been proposed for producing resin compositions with improved rigidity and heat resistance by simply adding inorganic fillers such as calcium carbonate, kaolin, and talc to polypropylene. However, inorganic fillers have poor bonding properties with polypropylene, and although adding inorganic fillers helps to improve rigidity, heat resistance, linear expansion coefficient, etc. to some extent, it does not improve the durability, which is a desirable property of polypropylene resin. Since it has the drawback of greatly impairing its impact resistance and excellent surface gloss, its usage has been severely restricted, and at the same time, the field of application of the product has also been severely limited. In order to improve these drawbacks, attempts have been made to surface-treat the inorganic filler to improve its bonding properties and affinity with polypropylene resin.

For example, surface treatment with silane coupling agents has been carried out, but although it is useful for improving tensile strength, rigidity, and heat resistance, it is hardly effective in preventing a decrease in impact resistance. Attempts have also been made to improve the bondability and affinity with polypropylene by blending a modified polypropylene resin grafted with a monomer or by polymerizing a polar monomer on the surface of an inorganic filler. However, even these have insufficient bonding properties with polypropylene, making it difficult to obtain a satisfactory composition.
Moreover, such a method has the disadvantage of requiring complicated steps to modify the inorganic filler or polypropylene, resulting in high costs. The modification of polypropylene resin that is required for practical purposes is of course necessary to greatly improve the desired mechanical properties, but it must be such that the desirable properties inherent in the polypropylene resin are minimally degraded.

Previously attempted polypropylene resin compositions containing inorganic fillers have not been able to simultaneously satisfy the above requirements. The present inventors have focused on the dispersibility of the inorganic filler and its affinity with the polypropylene resin as the technical points for creating a composite composition of an inorganic filler and a polypropylene resin, and the dispersibility and bonding of the inorganic filler with the polypropylene resin in a small amount. As a result of intensive research into the second component that improves properties, the combination of a specific amount of glycerin fatty acid ester and a specific amount of barium sulfate has been found to provide excellent rigidity and heat resistance without impairing the high impact resistance and surface gloss inherent to polypropylene resin. The present invention was achieved by discovering that a polypropylene resin composition can be provided.

That is, the polypropylene resin composition according to the present invention has (1
) Mainly composed of crystalline polypropylene-ethylene copolymer, 10 to 50 wt% of barium sulfate and 0.1 to 1.5 wt% of glycerin fatty acid ester are blended into the composition, and it has excellent rigidity, heat resistance, and impact resistance. and (2) a mixture of crystalline propylene-ethylene copolymer as a main component and barium sulfate and talc in a weight ratio of 50 to 80:
A polypropylene resin composition containing 10 to 40 wt% of a mixed filler having a molecular weight of 50 to 20 and 0.1 to 1.5 wt% of a glycerin fatty acid ester and having excellent rigidity, heat resistance, and impact resistance. It is.

The glycerin fatty acid ester used as the second component in the present invention has the following general formula (in this general formula, X is H or -
C-R and R is an alkyl group of C3 to C22), such as stearic acid monoglyceride, linoleic acid monoglyceride, behenic acid monoglyceride, ricinolenic acid monoglyceride, and these There are also compounds such as diglycerade.

Particularly preferred fatty acid glycerides are stearic acid monoglyceride, oleic acid monoglyceride, and behenic acid monoglyceride, and the amount added is 0.1 to 1.5%.
wt%, preferably 0.3 to 0.8 wt%.

If the amount added is less than 0.1 wt %, the dispersion of the inorganic filler and the bonding force with polypropylene will be insufficient, and a composition satisfactory in the present invention will not be obtained. In addition, even if it is 2.0wt% or more, the rigidity
Although it is possible to obtain a composition that is satisfactory in impact resistance and heat resistance, it has the drawback that the fatty acid glyceride is largely exposed and the surface becomes sticky. The inorganic filler added to polypropylene in the present invention is barium sulfate, which is generally commercially available as a filler, or a mixture of barium sulfate and talc.

In the present invention, the amount of barium sulfate used is 10 to 50 wt%, preferably 20 to 3 wt% in the polypropylene resin composition.
It is 0 Wt%.

When using a mixture of barium sulfate and talc, the amount added is 10 to 40 wt%, preferably 15 to 25 wt%.
is desirable. There are no particular technical difficulties in producing the novel polypropylene resin composition according to the invention.

For example, it can be produced by simultaneously kneading a polypropylene resin, an inorganic filler, and a fatty acid ester. The term "crystalline polypropylene ethylene copolymer" as used in the present invention means an essentially crystalline block copolymer of propylene and ethylene having a content of 20 wt % or less in the copolymer. The polypropylene resin composition obtained by the present invention has excellent filler dispersion and bonding strength between the filler and polypropylene, and has remarkable physical properties and surface gloss compared to a composition in which only an inorganic filler is added without adding fatty acid glyceride. The result is an effect that could not have been predicted by simply combining resin and filler or by using conventional additives.

The polypropylene resin composition of the present invention may also contain known stabilizers such as various antioxidants and ultraviolet absorbers conventionally used in polypropylene.

The amount used is the amount generally used for polypropylene. Examples are shown below to clarify the content of the present invention.

In addition, the bending strength, heat distortion temperature, and Izot value are as per ASTM.
' D747-63, ASTM D648・-56, AS
The Dupont impact strength values were measured according to TMD256-56 and JIS K67l8. Examples 1-2 Crystals with [η] 1.95 and ethylene content of 8.0 wt%
Monopropylene-ethylene copolymer, precipitated barium sulfate 20wt%, stearic acid monoglyceride 0.4W
t% and stabilizers such as 2,6-ditertiarybutyl para-cresol, 4,4thiobis(6-tert-butyl-m-
Cresol) Calcium stearate and dilaurylthiopropionate were added at 0.0% to polypropylene resin, respectively.
15 wt% was added, mixed for 3 minutes using a pen shell mixer, and then extruded using an extruder at a temperature of 190 to 210°C to form pellets.

Test pieces for measuring physical properties were molded from the pellets using a screw-in-line injection molding machine, and the bending strength, thermal deformation temperature Izot value, and Dupont impact strength were measured. Table 1 shows these measurement results in comparison with control examples (one in which only talc was used instead of precipitated barium sulfate, and one in which glycerin fatty acid ester was not added). Examples 3 to 5 Test pieces were prepared in exactly the same manner as in Example 1, except that 30 wt% of precipitated barium sulfate and glycerin fatty acid ester were shown in Table 2, and the physical property test results are shown in Table 2.

Examples 6 to 8 [η] 1.95, mixed filler of crystalline propylene-ethylene copolymer with ethylene content of 8.0 wt%, stearic acid monoglyceride 0.4 wt%, precipitated barium sulfate, and talc A test piece was prepared in exactly the same manner as in Example 1, except that the amounts listed in Table 3 were added, and the physical property test results are shown in Table 3.

Examples 9 to 11 Test pieces were prepared in exactly the same manner as in Example 1, except that 10 wt% precipitated barium sulfate, 10 wt% talc, and glycerin fatty acid ester were shown in Table 2, and the physical property test results are shown in Table 3. It was shown to.

Claims (1)

[Scope of Claims] 1. A composition mainly composed of crystalline propylene-ethylene copolymer, containing 10 to 50 wt% of barium sulfate (all wt% in the composition is shown below unless otherwise specified) and 0.1% of glycerin fatty acid ester. A polypropylene resin composition characterized by containing ~1.5 wt% of polypropylene and having excellent rigidity, heat resistance, and impact resistance. 2 10% of the mixed filler is mainly composed of crystalline propylene-ethylene copolymer and is a mixture of barium sulfate and talc in a weight ratio of 50 to 80:50 to 20.
~40wt% and glycerin fatty acid ester 0.1-1
．． A polypropylene resin composition containing 5 wt% of polypropylene and having excellent rigidity, heat resistance, and impact resistance.